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1. Field of the Invention
This invention relates to a weighing apparatus and, more particularly, to a multiple platform weighing apparatus utilizing a combined singular scale checking system.
2. Description of Prior Art
Many weighing applications such as large vehicle scales prefer the use of multiple platforms. A heavy capacity platform for weighing vehicles requires multiple load cells. Each load cell provides a signal proportional to the portion of the load borne by that load cell. In heavy capacity applications the load is usually distributed over at least four load cells and some applications may require sixteen or more load cells. The sum of the platform output signals must be obtained to provide a signal representative of the total weight applied to the scale
xe2x80x9cThe weight accuracy of multiple load cell scales depends not only on the accuracy of the individual cells, but also on the mechanical and electrical interaction among them. Since the load cells usually have different sensitivities to applied loads each platform output must be made independent of the position of the weight on the platform. In addition, each platform output comprising the multiple platform scale must be made independent of the position of the weight on the scale. The outputs of the individual cells must therefore be compensated or adjusted so that the total scale output remains substantially the same for a given load no matter where on the scale It is positioned. Such load position compensation has usually been accomplished by connecting sensitivity reducing resistors in the wheatstone bridge circuit of the individual load cells, usually across the output of the bridge circuit. U.S. Pat. No. 4,804,052 discloses the xe2x80x9cdigital load cellxe2x80x9d in which an analog-to-digital converter and microprocessor are dedicated to a single load cell.xe2x80x9d
xe2x80x9cA large capacity weigh scale usually consists of multiple load cells. Typically a rocker pin, double sheer beam torsion ring type load cell is used. U.S. Pat. No. 4,815,547 to Dillon et al. discloses a typical rocker pin with a printed circuit board attached. A principal advantage of the rocker pin is that it can be made self-erecting, so that when the normally upright pin is deflected about its base or grounded end the pin will return to its upright position when the deflecting load is removed. The self-erecting feature is an advantage in weighing applications in which temporary side loads are encountered. Tho self-erecting feature is obtained by configuring the pin so that the radius of curvature of each end surface is greater than half the total height of the pin.xe2x80x9d
A common vehicle scale configuration often contains a number of independent scale platforms thereby allowing the determination of vehicle axle or axle group weights in addition to the gross vehicle weight. These scales have often been combined longitudinally (lengthwise) utilizing tie rod type links which is a device that fixes relative motion between two objects connected using a tie rod link only in the direction along the axis of the link. The relative motion between two bodies connected using tie rod links in another direction is not constrained or has been constrained with other means such as bumpers. These bumpers can cause a xe2x80x9clive to deadxe2x80x9d weight problem if the bumpers are touching the platform causing the weight to be inaccurate. This can be a very big problem with the buildup of debris and ice. Therefore, these longitudinally tie rod links do not help to limit potential side checking interference.
There is still room for improvement within the art.
1. Field of the Invention
2. Description of Related Art Including Information Disclosed Under 37 CFR xc2xa7 1.97** greater than  and 1.98 less than .
It is a general object of the present invention to substantially eliminate the problems described above associated with connecting a number of independent platforms comprising a multiple platform scale. A more particular object is to eliminate potential checking interferences.
The present invention consists of a weighting method and weighing apparatus which includes a number of independent platforms comprising a multiple platform scale that allows the determination of vehicle axle weights in addition to gross vehicle weight. The current invention is a novel method of combining independent platforms enabling independent weighing on each platform and at the same time a singular checking system of the combined scale. This invention involves utilizing three tie rod type links, which in prior art have commonly been used to combine scales only longitudinally (lengthwise), however in the current invention they are also attached in the lateral (widthwise) direction. This allows the platforms to remain independent and utilize a simple single checking system for all platforms comprising the multiple platform scale.